- If, after conventional and dynamic MPI some of these patients do not have SCA, they will still be followed for events for up to 3 years following participation in the protocol. To avoid delays and unnecessary procedures among patients in Group II who will have the dynamic imaging protocol studies after SCA, patients will be selected for protocol enlistment only if the decision is made by the patient's physician, based totally on clinical and social factors, that any considered revascularization intervention would not be performed on the day of diagnostic SCA and will be performed electively, at least 4 to 7 days later.